If I may interject for a moment, I have been reading this post and I am utterly amazed at how much you guys know, how much knowledge you all have, AND THAT ISN'T SARCASM, I REALLY MEAN IT. It makes common folk like me realize how much we take for granite for some of the conveniences we have, we just buy a ticket on USAirways or whatever and expect to get to where we are going, NOT UNDERSTANDING that there are people out there who have to know how all this works. There are people out there who actually thought this stuff up and figured it all out. It's amazing, just a big eye opener. I don't claim to be dumb or anything, but it is just cool to see. A LITTLE OFF THE SUBJECT of thrust angles; I am a Biomedical Technician for the VA and I repair and maintain medical equipment and life support equipment and many people think my job is important, and it is, but it is people like you guys who invent the stuff I repair, and that to me is far more important. Although I do have to say that sometimes engineers who design some of the equipment don't have the end user or technician in mind as it can be a nightmare at times to repair. Thanks for listening to my 2 cents...